1. Field of the Invention
The invention relates to a decoding and regenerating device which decodes and regenerates frame coded data which is frame-coded on a channel-by-channel basis by sampling time series signals of a plurality of parallel channels and a decoding and regenerating method, and more particularly to a decoding and regenerating device for frame coded data which is characterized by a regenerative data buffer means for giving regenerative data to a data regenerating means at the appropriate times, and to a decoding and regenerating method.
2. Description of the Related Art
In the case of time series signals such as voice signals and music signals, the time series signals of a plurality of parallel channels are sampled, and with a predetermined time interval determined as one frame period, the signals are frame-coded on a frame-by-frame basis consisting of a plurality of samples contained in a single frame period with respect to the respective channels and stored in a medium, and desired frame coded data may be decoded and regenerated by a decoding and regenerating device.
Conventionally, such a decoding and regenerating device as shown in FIG. 7 is provided with two groups of regenerative data buffer memories 60, 70 which contain frame memories for storing regenerative data for the number of samples of one frame, for all channels. And, regenerative data decoded by a decoding unit 20 is stored into the regenerative data buffer memories 60, 70 and alternately outputted in every frame period from the memories 60, 70 to a data regenerating unit 50.
FIG. 8 is a flowchart illustrating the operation of a conventional decoding and regenerating device for frame coded data.
Referring to the flowchart of FIG. 8, the decoding unit 20 reads to decode frame coded data for one frame of the respective channels in the first frame period and stores the obtained regenerative data into the regenerative data buffer memory 60 (steps 801, 802).
Then, it is judged whether the frame in question is a final frame by the decoding unit 20 (steps 803, 804) and when it is a final frame, the data regenerating unit 50 completes its processing after regenerating the regenerative data which is stored in the regenerative data buffer memory 60 (step 805). When it is not a final frame, the data regenerating unit 50 regenerates the regenerative data which is stored in the regenerative data buffer memory 60 (step 806), and the decoding unit 20 reads to decode the frame coded data for the next one frame at every channel and stores the obtained regenerative data into another regenerative data buffer memory 70 (step 807).
And, the frame in question is judged whether it is a final frame (steps 808, 809), and when it is a final frame, the data regenerating unit 50 completes the processing after regenerating the regenerative data which is stored in the regenerative data buffer memory 60 (step 810). When it is not a final frame, the data regenerating unit 50 regenerates the regenerative data which is stored in the regenerative data buffer memory 70 (step 811), reads to decode the frame coded data for the next single frame at every channel, and stores again the obtained regenerative data into the regenerative data buffer memory 60 (step 812).
As described above, the regenerative data alternately decoded in every frame period is stored by the two groups of regenerative data buffer memories 60, 70. The regenerative data is given to the data regenerating unit 50. Thus, the frame coded data of the plurality of parallel channels are decoded and regenerated.
As described above, the conventional decoding and regenerating device for frame coded data has disadvantages that it needs two groups of regenerative data buffer memories to store regenerative data, resulting in hindering the device from being made compact and raising the cost.